Transverse abrasive blast tube



R. G. MILLHISER 3,160,989

TRANSVERSE'. ABRASIVE BLAST TUBE Dec. 15, 1964 Filed April 27, 1961 AND C PUMP MOTOR ER ULl TIM HYDRA INVEN TOR. ROBERT G.Ml LLHISER ea nC/Lg 9/'/'/S ;%y d,

ATIQRNEYS 3,160389 TRANSVERSE AERASIVE BLAST TUBE Robert G. Millhiser, Detroit, Mich, assignor to Ajern Laboratories, Inc., Livonia, Mich. Filed Apr. 27, 1961, Ser. No. 105,978 12 Claims. (Cl. 51--8) This invention relates to an improved surface reforming device, such as a deburring, abrading, or blast-peening device. More particularly the invention relates to a device in which surface reformation of parts having internal cavities can be effected.

Many problems are presented in the manufacture of metal parts, especially metal castings and machined parts having burrs, scoring, threads or other surface imperfections, or stresses tending to initiate failure, which require surface treatment, for example to remove scale flash burrs and the like or to alter the surface micro-structure. This can be elfected'by wet blasting with hard granular ma terials, such as shot-peening or wet blasting with abrasive grains. In such treatments there is achange in the surface of the part acted on, either to remove surface material or to change its micro-structure, and the term surface reforming will be used herein to refer to such treatment. 1

The wet blasting of the present invention is not to be confused with sand blasting and similar procedures as heretofore used which have been accompanied by serious hazards to health, a serious dust nuisance and sometimes fire hazards. Moreover, the abrasive effects of the sand or other hard granular material, cause rapid deterioration and eventual destruction of necessary equipment. Also, the high energy and hard particles used in the surface reforming with which the present invention is concerned is very different from'washing procedures used, forexample, inbottle washing, where suspensions of soft lead shot or'pieces of rubber in water or detergent solution have been employed, and the suggested washing of automobiles by pieces of rubber sponge carried in streams of water. i

In such operation, the solids were yielding and soft to avoid change in surface finishes, and damage to equipment used. The velocities and kinetic energies have been kept far below those which would result in changing or reforming the surfaces treated.

In the copending application of my co-workers Umb'richt and Johnson, Serial No. 9,910, filed February 19, 1960, a new method of surface reforming is described and claimed. A clear liquid such as Water or washing solution is forced, usually by high pressure, through orifices to form a high speed jet directed into the rear end (with respect to the direction of flow) of an ejector tube. A concentrated but fluent suspension of blasting grains is supplied to said blast tube. By fblastinggrains I mean a granular material which, by impact on the surface to be reformed, serve effectively for the surface reforming operation. These particles may be various grits, sands dlbhfidd Patented Dec. 15, 1964 that the blast should be vertically directed, as the grit etc. had to settle around the intake end of the blast tube, and any changes of direction result in abrading of the apparatus. The parts to be treated have been turned and shifted relative to the blast tubes for orienting them to the blast. Thus it has been possible to treat very effectively the external surfaces, and in some cases even internal surfaces of larger cavities, e.g., in automotive axle housings, etc. However, it is often inconvenient or expensive to thus shift aroundthe articles to be treated and some parts having small drilled holes and central cavities with narrower openings are difficult to treat effectively. Internal burrs and other undesired material which should be removed from bores or cavities, etc., cannot effectively be treated because the jets do not reach them or do not strike them at an effective angle.

The present invention provides for jet blasting of upwardly facing, steeply sloping, or vertical surfaces and/ or internal surfaces with effective reforming thereof; and it provides for accurately located effects. One aspect of the invention provides portable grit containers with appropriately located and directed blast tubes and these may be inserted bodily into cavities or channels within the parts being treated. One'important aspect of the invention is providing a manifold having a pluralityof jets arranged for registry with a corresponding plurality of areas, or holes, to be treated and relatively movable with respect to each article to bring said jets into close proximity to said holes or areas as it is positioned for such treament; and subsequently separating the manifold from the article to free the article for transfer away from said position and to replace it by another article in' registry other localized surfaces to be treated. A jet tube for high pressure liquid extends down into this vessel; and near its bottom are appropriately located jet nozzles, or openings, which register the short blast tubes, and which are generally laterally or downwardly directed through said blast tubes to said holes or localized areas.

When -a part for which this apparatus is designed is held adjacent to the blast tubes, vertical faces as well as small cavities, drilled holes, etc., aligned with the blast tubes, can be effectively subjected to action of the blast of or, in the case ofpeening, may be smooth grains, e.g.

steel shot, fine'pebbles, and the like.

The jetspick up and accelerate surface-reforming jets,yvery effective surface reforming results. Normally jthe jets are directed through blast tubes, which jets not only serve as ejectors to pick up and accelerate the blast grains, but also direct and concentrate their action on desired holes or other areas and maintain the requisite grains by ejector action; and, when an object, the surface 1 of'which is to be reformed, is'placed in the path of the ever, it had seemed to be a limitation of this process liquid and surface-reforming granules, and effective surface reforming results. Where, as illustrated, the surfaces to be treated extend off from an internal cavity or bore, the blast tubes can be lined up either by moving the slurry vessel with its blast tubes, etc. into the cavity or with the tube in fixed position, by moving the part to effect thesame relation.

Parts of innumerable shapes can be treated by the present invention with, of course, corresponding designs of slurry vessels with jets and blast tubes arranged to be directed at eifective angles against particular areas re- .quir-ing treatment.

In the accompanying drawings I have shownandhave described herein one example of the practical application of my invention and have suggested certain alternatives and modifications therof, These are given for purposes of illustration and explaining the invention and its practical application and the principles thereof, so that others skilled in this art will be enabled to modify and apply the invention various forms eaohwas may be best suited to the requirements of a particular use.

" The invention will now be described particularly in conjunction with the drawings in which:

The single figure is a view partly in elevation and partly The blast in vertical axial section, of a jet blasting device and a fragment of the part to be treated.

In the drawing, the part to be treated is illustrated as a rear bearing retainer 1. This retainer has three transverse drilled holes 2. Burrs or other undesired surface features on the outside of this article 1 are easily corrected by methods described and claimed in copending app ications filed herewith and heretofore. However, internal burrs, such as are shown greatly exaggerated at 3, have presented a more difiicult problem.

A vessel, or container, 4 for holding a supply of a slurry of grit or other treating material is shown with a hopperlike form and a restricted chamber at its lower end surrounding the cavity of the retainer and with three short blast tubes 5 aligned respectively with the holes 2. A pipe 6 provided with openings or jet orifices 7 aligned with the blast tubes 5 supplies liquid under high pressure and serves as a manifold for the jets 7. The end of this tube is closed and may be off center to minimize the space required in the chamber 4.

Violent, substantially horizontal jets from orifices 7 strike, pick up and impel abrasive slurry in the chamber 4 and impel it through the stubby blast tubes 5 against the periphery of and into the holes 2 in the bearing retainer, and reform the surfaces, for example by removing the internal burrs 3.

The part being treated may be rotated with respect to the hopper, or vice versa, especially if there is a circumferential series of holes. Such rotation may also serve to reform the surface progressively around the internal cavity 8 of the bearing retainer. For example, the blasts may be aligned with the holes 2 until the burrs 3 are removed and a slight rounded edge produced around the holes, and then the part maybe rotated about the axis of the manifold pipe 6.

The blast of surface reforming particles after having done their work on the bearing retainer can be recovered and reused, with or without washing. In any case the supply of such material around the jets 7 will be continually replenished by material added to the vessel 4.

A hose 13 is shown as a diagrammatic representation of the means for replenishing the supply of grit or other treating slurry.

When surface reforming of the inner cavity bearing retainer is complete the supply of liquid to pipe 6 is stopped by valve for an intermittent period while the part is moved away from the vessel 4 until treatment of the next part can begin. (See the upper portion of the drawing where the conventionally actuated valve mechanism 15 is diagrammatically illustrated as including a hydraulic system and a timer which are operatively cocx dinated with the functioning of the registering means 12, the latter being alternatively referred to as the elevator 12 and being illustratively shown as a hydraulic motor.) Or, if more convenient, the vessel 4 may be removed from the cavity so that the part can move in the same straight line.

In the illustrated embodiment the vessel 4 is adjustably supported on frame members 9 by a tube 10 which is adapted to be secured in a given position thereon, e.g., by being provided with an ear or lug 11 to which is attached an elevator device 12. When the elevator 12 raises the vessel 4 suflicient-ly to clear the bearing retainer 1, the part may move on and be replaced by another, whereupon the elevator 12 lowers the blasting device to the bottom of the recess 8 and the sequence of operations described above is repeated.

Usually a cleaning or scouring operation will precede the internal deburring which has been described above and these may effect a suflicient reforming of the interior surface of the cavity 8. However,-in some cases it may be preferable to reform this surface also by means of a simultaneous or subsequent blasting in accordance with the present invention. This can be done by providing a small blast tube 5a in the bottom of the hopper 4 with a small opening 7a in the bottom of the tube 6 registering therewith. (These are shown in the drawing but are not essential.) As the part turns or the slurry vessel 4 turns this will reform the surface 14 of the cavity. Ordinarily with such large cavities, however, the preceding surface reforming operations will be adequate.

Although the present invention has great advantage for treating interior surfaces and lateral cavities and passages in hollow parts, it is not limited to that. In cases where it is not convenient to rotate a part in a vertical jet, the invention may be used with advantage to treat vertical, and

near vertical, surfaces and recesses from such external surfaces.

In the detailed description of the embodiment shown in the drawings the hopper and water jet tube is vertical and the blast tubes, or most of them, are horizontal. This is not essential. It is an advantage of this invention that the hopper can be inclined and so can the blast tubes.

The blast tubes 5 and 5a are shown as replaceable inserts of abrasion resisting material, as they are the only part of the apparatus subjected to any abrasive action of the blast.

In the illustration the right angle jets of blast tubes 5 have been shown all on one side of the end of the hopper 4. With the particular design of bearing retainer shown this is desirable because all of the holes drilled in the retainer are in the same axial plane. Other parts may have holes drilled at different points around a cavity, and in such cases of course the blast tubes should be suitably oriented, or in some cases the turning of the piece to be treated with respect to the hopper 4 may permit blasts to strike successive holes.

The present invention performs a function that was not possible before, namely an effective surface reforming of surfaces of manufactured parts and especially inside of hollow articles and of tributary recesses transverse to a main recess. This new function is, of course, a most important feature of the present invention, but it should be noted that there is a further advantage. Whereas, here tofore reforming of the surfaces of cavities has been done by fixed blasts with the parts moved to and past them, in the case of the present invention illustrated herein, the surface reforming of the internal surfaces is effected with small portable blast device which is inserted into the cavity. This is an additional advantage, presenting the unusual situation where an improvement which performs a new and valuable function has no offsetting disadvantages, and actually effects a further economy.

The present invention eliminates practically entirely any wear on the pumps and other equipment which produces the high speed water jets. However, the suspension of surface reforming material does strike the blast tubes 5. These, therefore, are preferably made of highly abrasion resistant material, for example, very hard alloys containing high amounts of manganese or other wear resistant surfaces such as rubber. Nevertheless some wear takes place and it is an added advantage of the present invention that the blast tubes can be quickly replaced when they have worn to the point that this becomes necessary. New tubes can be pressed into the hopper 4 or they can be threaded to mate with threaded openings in the hopper 4. Replacement is quick and new blast tubes are small in size and of simple shapes so that the cost of replacement is very moderate.

What is claimed as new is:

1. A device for surface reforming of an article surface comprising'supply means for furnishing a fluent supply of blast granules, at least one blast tube having a central bore positioned to receive blast granules from'said supply means andextending through a wall, which contains said granules, of said supply means with its discharge end opened outward therebeyond, and jet means for introducing a high pressure liquid jet with surface reforming energy into a portion of said supply means adjacent to, and out through,'said blast tube whereby said blast granules are entrained in said jet for projection as an abrasive liquid jet through the access provided by the blast tube and against the surface to be reformed,

the bore of said blast tube being large enough to accommodate the respective abrasive liquid jet streaming therethrough whereby the wear of said blast tube is minimal.

2. A jet device for hydraulic blast surface reforming of articles having a plurality of holes with a liquid suspension of abrasive granules which comprises a manifold having therein a plurality of jet orifices arranged in a pattern adapted for alignmennrespectively, as to position and direction corresponding with a plurality of holes arranged on a like pattern in an article to be blasted thereby, blast tubes aligned with said orifices, liquid suspension supply means for supplying blasting granules to the inlet ends of said blast tubes, said blasting tubes extending through a wall of said supply means which contains said liquid suspension, means for effecting controlled relative movement between said article and said manifold to bring said orifices through their respective blast tubcs into registry with said holes, and means for supplying liquid under high pressure to said manifold to produce jets for entraining and driving said blasting granules as abrasive blasts through said blast tubes with surface reforming energy, said tubes being large enough substantially to accommodate the abrasive blast therethrough whereby the wear thereof is minimal.

3. A device as defined in claim 2 which further includes shut-off means for intermittently supplying liquid under pressure to said jets, said shut-off means supplying such liquid when said jet orifices are in registry with said holes and shutting off the liquid when not so registered.

4. Apparatus for surface reforming of surfaces'of parts comprising a container for a fluent wetted mass of blast granules, a portion of said container being adapted for positioning adjacent said surfaces, a plurality of blast tubes in said portion of said container and disposed therein for precise spacial registry and alignment with said surfaces, means for injecting hyraulic blasting impeller liquid at high pressure and velocity into said portion of said container to entrain said blast granules therein and to eject said blast granules through said blast tubes as an abrasive blast with surface reforming velocity and energy against said surfaces of said parts to be reformed, said blast tubes being large enough substantially to accommodate the abrasive blast therethrough whereby the wear thereof is minimal.

5. Apparatus for surface reforming of surfaces of parts comprising a container for a fluent wetted mass of blast granules, a portion of said container being adapted for positioning adjacent said surfaces, a plurality of blast tubes in said portion of said container and disposed therein for precise spacial registery and alignment with said surfaces, means for injecting hydraulic blasting impeller liquid at high pressure and velocity into said portion of said container to entrain said blast granules therein'and to eject said blast granules through said blast tubes as an abrasive blast with surface reforming velocity and energy against said surfaces of said parts to be reformed, said blast tubes being large enough substantially to accommodate the abrasive blast therethrough whereby the wear thereof is minimal, and means for moving said container into and out of register with said surfaces, internal cavities, and passages of each said part to be treated.

6. Apparatus as recited in claim 5 which-also includes means for shutting off said means for injecting hydraulic blasting impeller liquid when said container is out of register with said internal cavities and passages to be treated.

7. A device for surface reforming of article surfaces comprising in combination a supply vessel having a wall for holding a fluent supply of wetted blast granules and feeding them in the mouth of a blast tube, at least one blast tube with its mouth positioned in the lower part of said supply vessel to receive said blast granules therefrom and extending through the wall of said vessel with its discharge end opened outward 'therebeyond, a jet tube for high pressure liquid extending into said vessel to adjacent said blast tube and provided with jet orifice aligned with said blast tube, means for supplying liquid under high pressure to said jet tube for producing an impeller jet to entrain and drive said blast granules as an abrasive jet.

through said blast tube with surface reforming energy, said blast tube being large enough substantially to accommodate any resulting surface reforming blast therethrough whereby the wear thereof is minimal.

8. A device as defined in claim 7, in which the end of said vessel is dimensioned to enter a cavity in an article the internal surface of which is to be reformed.

9. A device according to claim 7 in which said blast tube is at substantially right angles to the long dimension of the supply vessel.

10. A device according to claim 9 in which said supply vessel is shaped near its lower end to be closely spaced from the jet tube with space for flow of said granules into the mouth of the blast tube, and the vessel above said end is funnel-shaped for gathering of said granules into said lower end adjacent the blast tube.

11. A device for surface reforming of article surfaces comprising in combination a supply vessel having a wall for holding a fluent supply ofwetted blast granules and feeding them in the mouth of a blast tube, at least one blast tube with its mouth positioned in the lower part of said supply vessel to receive said blast granules therefrom and extending through the wall of said vessel with its discharge end opened outward therebeyond, a jet tube for high pressure liquid extending into said vessel to adjacent said blast tube and provided with jet orifice aligned with said blast tube, said blast tube being large enough substantially to accommodate any resulting surface reforming blast therethrough whereby the wear thereof is minimal, and registering means for intermittently approaching and retracting the supply vessel from the surface to be reformed. 12. A device according to claim 11 in which shut-off means is provided for intermittent supply of liquid under pressure to said jet tube, said shut-off means being synchronized with said registering means to cut off said supply when the supply vessel is retracted from the surface being reformed.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain June 28, 1934 

1. A DEVICE FOR SURFACE REFORMING OF AN ARTICLE SURFACE COMPRISING SUPPLY MEANS FOR FURNISHING A FLUENT SUPPLY OF BLAST GRANULES, AT LEAST ONE BLAST TUBE HAVING A CENTRAL BORE POSITIONED TO RECEIVE BLAST GRANULES FROM SAID SUPPLY MEANS AND EXTENDING THROUGH A WALL, WHICH CONTAINS SAID GRANULES, OF SAID SUPPLY MEANS WITH ITS DISCHARGE END OPENED OUTWARD THEREBEYOND, AND JET MEANS FOR INTRODUCING A HIGH PRESSURE LIQUID JET WITH SURFACE REFORMING ENERGY INTO A PORTION OF SAID SUPPLY MEANS ADJACENT TO, AND OUT THROUGH, SAID BLAST TUBE WHEREBY SAID BLAST GRANULES ARE ENTRAINED IN SAID JET FOR PROJECTION AS AN ABRASIVE LIQUID JET THROUGH THE ACCESS PROVIDED BY THE BLAST TUBE AND AGAINST THE SURFACE TO BE REFORMED, THE BORE OF SAID BLAST TUBE BEING LARGE ENOUGH TO ACCOMMODATE THE RESPECTIVE ABRASIVE LIQUID JET STREAMING THERETHROUGH WHEREBY THE WEAR OF SAID BLAST TUBE IS MINIMAL. 